A non-ionic dispersing agent

ABSTRACT

A nonionic dispersing agent suitable for use in the production of aqueous polyurethane dispersions, said agent having the formula: ##STR1## wherein R 1  represents a monovalent hydrocarbon radical containing 1-12 carbon atoms; 
     R 2  represents hydrogen or a mixture thereof with methyl and/or ethyl, at least 40% of the R 2  substituents in said mixture being hydrogen; 
     R 3  represents an isocyanate-reactive organic radical; 
     R 4  represents H or an isocyanate-reactive organic radical; 
     Z represents an alkylene radical containing 2-4 carbon atoms; 
     m is an integer from 5 to 150, and 
     n is 0 or 1.

This invention relates to nonionic dispersing agents useful in theproduction of nonionic water-dispersible polyurethanes, to thewater-dispersible polyurethanes and to the derived aqueous polyurethanedispersions.

Aqueous polyurethane dispersions are well known and are employed in theproduction of useful polyurethane products for example coatings andfilms. Dispersion of the polyurethane in the aqueous system has beenachieved by the use of either external or internal dispersing oremulsifying agents but, in general, the internal agents, which can beionic or nonionic, have been found to be more satisfactory.

Water-dispersible polyurethanes of nonionic character generally owetheir dispersibility to the presence of pendent polyoxyethylene chainsalong the main polyurethane backbone, methods for the incorporation ofsuch chains having been described in, for example, U.S. Pat. Nos.3,905,929 and 3,920,598.

In the process described in U.S. Pat. No. 3,905,929, diols havingpolyethylene oxide side chains are prepared by reacting an organicdiisocyanate with a polyethylene glycol mono-ether to form amonoisocyanate containing polyethylene oxide units which is then reactedin stoichiometric proportions with a dialkanolamine. The resultingdiols, together with conventional diols, are then reacted withdiisocyanates to form polyurethanes which, because of the pendentpolyoxyethylene chains, are water-dispersible.

In the process described in U.S. Pat. No. 3,920,598, diisocyanateshaving polyethylene oxide side chains are prepared by reacting two molesof a diisocyanate with one mole of a polyethylene glycol monoether, theinitially formed urethane monoisocyanate then being reacted at a highertemperature with the excess diisocyanate to form an allophanatediisocyanate having a pendent polyoxyethylene chain. Correspondingbiuret diisocyanates are also described. The allophanate or biuretdiisocyanates, together with conventional diisocyanates, are thenreacted with diols to form polyurethanes which, because of the pendentpolyoxyethylene chains, are water-dispersible.

Neither of these methods of making dispersing agents for incorporationinto polyurethanes is completely satisfactory however because of theneed to use expensive diisocyanates and because of the formation ofundesirable by-products.

It has now been found that certain novel polyoxyalkylene amines ashereinafter described are excellent dispersing agents and may beincorporated into polyurethanes to provide water-dispersibility. Thesaid polyoxyalkylene amines can be prepared from relatively low costmaterials and they can be used at lower levels than the above mentionedprior art dispersing agents. Furthermore, the dispersions obtained aremore stable than the prior art dispersions over a range of conditions.

Accordingly, the invention provides nonionic dispersing agents havingthe general formula: ##STR2## wherein R¹ represents a monovalenthydrocarbon radical containing 1-12 carbon atoms;

R² represents hydrogen or a mixture thereof with methyl and/or ethyl, atleast 40% of the R² substituents in said mixture being hydrogen,

R³ represents an isocyanate-reactive organic radical;

R⁴ represents H or an isocyanate-reactive organic radical;

Z represents an alkylene radical containing 2-4 carbon atoms;

m is an integer from 5 to 150, and

n is 0 or 1.

Examples of monovalent hydrocarbon radicals which may be represented byR¹ include C₁ to C₁₂ alkyl radicals, C₄ to C₈ cycloalkyl radicals, C₆ toC₁₅ aryl radicals and C₇ to C₁₀ aralkyl radicals. Preferably, R¹ is a C₁to C₄ alkyl radical, especially methyl.

The identity of R, is such that the --CH₂ CHR² O⁻ units are oxyethyleneunits or a mixture of oxyethylene units with oxypropylene and/oroxybutylene units, at least 40% of said units being oxyethylene. When amixture of such units is present, they may be arranged randomly or inblocks. It is preferred that at least 60% of the oxyalkylene units areoxyethylene units.

The radical represented by R³ (and R⁴ when not hydrogen) is an organicradical containing an isocyanate-reactive group, for example --OH, --SH,--COOH, --PO₃ H₂ and --NHR in which R represents hydrogen or optionallysubstituted alkyl. As specific examples of isocyanate-reactive radicals,there may be mentioned hydroxyalkyl, hydroxyalkoxyalkyl,hydroxy(polyalkyleneoxy) alkyl and hydroxyalkoxycarbonyl alkyl.

The alkylene radical represented by Z may be an ethylene, trimethylene,1,2-propylene or butylene radical.

It is preferred that m is an integer in the range from about 10 to about70.

One class of nonionic dispersing agents within the general class definedby Formula I has the formula: ##STR3## wherein R¹, R², Z and m have themeanings given above; R⁵ represents hydrogen, methyl or ethyl; p is aninteger from 1 to 100, and x is 1 or 2.

In the compounds of Formula II, it is preferred that Z is a1,2-propylene radical wherein the secondary carbon atom is attached tothe nitrogen atom. It is also preferred that R⁵ is hydrogen and that pis 1.

The compounds of Formula I may be prepared by reacting a primary amineof the formula: ##STR4## with at least one alkylene oxide of theformula: ##STR5## wherein R¹, R², R⁵, Z and m have the meanings givenabove, at least 40% of the R² substituents being hydrogen.

The reaction between the primary amine and the alkylene oxide may beperformed under standard oxyalkylation conditions. Thus, temperatures offrom about 80° C. to 180° C. may be employed and alkaline catalysts maybe used if necessary, for example when adding more than two moles ofalkylene oxide per amino group.

Primary amines of Formula III are commercially available. Examples ofsuch amines wherein Z is 1,2-propylene are the Jeffaminepolyoxyalkyleneamines available from the Texaco Chemical Company. Amineswherein Z is trimethylene may be obtained by the cyanoethylation ofpolyalkylene glycol mono-ethers followed by hydrogenation.

The alkylene oxide of Formula IV is preferably ethylene oxide.

A second class of nonionic dispersing agents within the general classdefined by Formula I has the formula: ##STR6## wherein R¹, R² Z,m and xhave the meanings given above;

R⁶ represents hydrogen, halogen or C₁₋₄ -alkyl:

Q represents a divalent electron-withdrawing group,

T presents a divalent hydrocarbon radical which may carry substituentsor contain hetero atoms, and XH represents an isocyanate-reactive group.

In the compounds of Formula V and Formula VI, it is preferred that Z isa 1,2-propylene radical wherein the secondary carbon atom is attached tothe nitrogen atom.

Halogen atoms which may be represented by R⁶ in the compounds ofFormulae V and VI include chlorine but it is preferred that R⁶ ishydrogen or methyl.

Examples of electron withdrawing groups which may be represented by Qinclude --CO--, --COO--, SO--, SOO--,SO₂ O and CONR in which R ishydrogen or alkyl.

Hydrocarbon radicals which may be represented by T include alkylene,arylene and mixtures thereof, said radicals optionally carryingsubstituents or containing hetero-atoms. Examples of suitable radicalsinclude alkylene radicals containing from 1 to 12 carbon atoms,oxyalkylene and polyoxyalkylene radicals of the formula --(CH₂ CHR²O)--wherein R² is as defined above and is from 1 to 10, phenylene anddiphenylene radicals and other arylene radicals such as ##STR7## whereinY is --O--, --S--, --CH₂ --, --CO-- or --SO₂ --

Isocyanate-reactive groups which may be represented by --XH in thecompounds of Formula V include --OH, --SH, --COOH, --PO₃ H₂ and --NHR inwhich R represents hydrogen or an alkyl radical.

The compounds of Formula V may be prepared by reacting one mole of aprimary amine of Formula III with one or two moles of an unsaturatedcompound of the formula: ##STR8## wherein R⁶,Q,T and XH are as definedabove.

by

The compounds of Formula VI may be prepared reacting one mole of aprimary amine of Formula III with one half mole of an unsaturatedcompound of the formula: ##STR9## wherein R⁶, Q and T are as definedabove.

The reaction between the primary amine of Formula III and theunsaturated compound of Formula VII or Formula VIII may be performedunder standard Michael addition conditions, solvents being used wherenecessary. Examples of unsaturated compounds of Formula VII particularlyinclude 2-hydroxyethyl and 2-hydroxypropyl acrylates and methacrylates.

Examples of unsaturated compounds of Formula VIII especially includediacrylates and dimethacrylates wherein T is a C₄₋₁₀ - alkylene residue,a polyoxyalkylene residue or an oxyethylated Bisphenol A residue.

A third class of nonionic dispersing agents within the general classdefined by Formula I has the formula: ##STR10## wherein R¹, R², R³, R⁴ Zand m are as defined above.

In the compounds of Formula IX, it is preferred that Z is an ethyleneradical or a 1,2-propylene radical wherein the secondary carbon atom isattached to the carbonyl group. It is also preferred that R³ ishydroxyethyl or hydroxypropy) and that R⁴ is selected from hydrogen,hydroxyethyl and hydroxypropyl. The compounds of Formula IX may beprepared by reacting an unsaturated ester of the formula: ##STR11##wherein R¹, R² and m are as defined above and R⁷ represents hydrogen,halogen or C₁₋₄ - alkyl, with a primary or secondary amine of theformula:

    R.sup.3 R.sup.4 NH                                         XI

wherein R³ and R⁴ are as defined above.

Compounds of Formula X may be obtained by reacting a polyglycolmono-ether of the formula: ##STR12## wherein R¹, R² and m are as definedabove with an unsaturated acid of the formula: ##STR13## wherein R⁷ isas defined above, or with an ester-forming derivative thereof, forexample a lower alkyl ester of said acid using ester interchangeconditions. Ester-forming derivatives of acids of Formula XIII which maybe used in the preparation of unsaturated esters of Formula X includethe methyl and ethyl esters of acrylic and methacrylic acids.

Amines of Formula XI which may be used in the preparation of nonionicdispersing agents of Formula IX include isopropanolamine anddi-isopropanolamine and, especially, ethanolamine and diethanolamine.

The dispersing agents of the invention may be used in the preparation ofnonionic water-dispersible polyurethane prepolymers.

Thus, in a second aspect of the invention, there is provided a nonionic,water-dispersible, isocyanate-terminated polyurethane prepolymercomprising the reaction product of:

(i) an organic polyisocyanate;

(ii) at least one organic polyol having a molecular weight in the range62 to 6000, and

(iii) a dispersing agent of Formula I.

The polyisocyanate used in making the prepolymer may be an aliphatic,cycloaliphatic, araliphatic or aromatic polyisocyanate. Examples ofsuitable polyisocyanates include ethylene diisocyanate,1,6-hexamethylene diisocyanate, isophorone diisocyanate,cyclohexane-1,4-diisocyanate, 4,4'-dicyclohexylmethane diisocyanate,p-xylylene diisocyanate, 1.4-phenylene diisocyanate, 2,4-toluenediisocyanate, 2,6-toluene diisocyanate, 4,4'-diphenylmethanediisocyanate, 2,4'-diphenylmethane diisocyanate, polymethylenepolyphenyl polyisocyanates and 1,5-naphthylene diisocyanate. Mixtures ofpolyisocyanates can be used and also polyisocyanates which have beenmodified by the introduction of urethane, allophanate, urea, biuret,carbodiimide, uretonimine or isocyanurate residues.

Organic polyols having molecular weights in the range 62-6000 which maybe used in the preparation of the prepolymer particularly include diolsand triols and mixtures thereof but higher functionality polyols may beused, for example as minor components in admixture with diols. Thepolyols may be polymeric polyols having molecular weights in the range400 to 6000 or low molecular weight polyols having molecular weightsbelow 400 depending upon the degree of flexibility desired in the finalproduct. Mixtures of polymeric and/or low molecular weight polyols maybe used.

The polymeric polyols may be members of any of the chemical classes ofpolymeric polyols used or proposed to be used in polyurethaneformulations. In particular, they may be polyesters, polyesteramides,polyethers, polythioethers, polycarbonates, polyacetals, polyolefins orpolysiloxanes. Preferred molecular weights are from 700 to 3000.

Polyester polyols which may be used include hydroxyl-terminated reactionproducts of polyhydric alcohols such as ethylene glycol, propyleneglycol, diethylene glycol, neopentyl glycol, 1,4-butanediol, furandimethanol, cyclohexane dimethanol, glycerol, trimethylolpropane,triethanolamine or pentaerythritol or mixtures thereof, withpolycarboxylic acids, especially dicarboxylic acids or theirester-forming derivatives, for example succinic, glutaric and adipicacids or their methyl esters, phthalic anhydride or dimethylterephthalate. Polyesters obtained by the polymerisation of lactones,for example caprolactone, in conjunction with a polyol may also be used.Polyesteramides may be obtained by the inclusion of amino-alcohols suchas ethanolamine in polyesterification mixtures.

Polyether polyols which may be used include products obtained by thepolymerisation of a cyclic oxide, for example ethylene oxide, propyleneoxide or tetrahydrofuran or by the addition of one or more such oxidesto polyfunctional initiators, for example water, ammonia, ethyleneglycol, propylene glycol, diethylene glycol, cyclohexane dimethanol,glycerol, trimethylolpropane, pentaerythritol, triethanolamine, aniline,ethylene diamine, toluene diamine, diaminodiphenylmethane, polymethylenepolyphenylene polyamines or Bisphenol A. Especially useful polyethersinclude polyoxypropylene diols and triols,poly(oxyethylene-oxypropylene) diols and triols obtained by thesimultaneous or sequential addition of ethylene and propylene oxides toappropriate initiators and polytetramethylene ether glycols obtained bythe polymerisation of tetrahydrofuran.

Polythioether polyols which may be used include products obtained bycondensing thiodiglycol either alone or with other glycols, dicarboxylicacids, formaldehyde, aminoalcohols or aminocarboxylic acids.

Polycarbonate polyols which may be used include products obtained byreacting diols such as 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol,diethylene glycol or tetraethylene glycol with diaryl carbonates, forexample diphenyl carbonate, or with phosgene.

Polyacetal polyols which may be used include those prepared by reactingglycol or hexanediol with formaldehyde. Suitable polyacetals may also beprepared by polymerising cyclic acetals.

Suitable polyolefin polyols include hydroxy-terminated butadiene homoand copolymers.

Organic polyols having molecular weights below 400 which may be used inthe preparation of the prepolymer particularly include diols and triolsand mixtures thereof but higher functionality polyols may be used.Examples of such lower molecular weight polyols include ethylene glycol,diethylene glycol, 2,2-dimethylolpropionic acid, tetraethylene glycol,bis(hydroxyethyl) terephthalate, cyclohexane dimethanol, furandimethanol, glycerol, triethanolamine and the reaction products, up tomolecular weight 399, of such polyols with propylene oxide and/orethylene oxide.

The non-ionic, water dispersible isocyanate-terminated polyurethaneprepolymer may be prepared in conventional manner by reacting astoichiometric excess of the organic polyisocyanate with at least oneorganic polyol having a molecular weight in the range 62 to 6000 and thedispersing agent of Formula I under substantially anhydrous conditionsat a temperature between about 30° C. and about 130° C. until reactionbetween the isocyanate groups and the hydroxyl groups is substantiallycomplete. The polyisocyanate and the active hydrogen containingcomponents are suitably reacted in such proportions that the ratio ofnumber of isocyanate groups to the number of hydroxyl groups is in therange form about 1.1:1 to about 6:1, preferably within the range of from1.5:1 to 3:1.

The dispersing agent of Formula I is suitably used in such proportionsthat the polyurethane prepolymer contains from 2 to 30%, preferably from5 to 20%, by weight of side chain polyethylene oxide segments.

If desired, catalysts such as dibutyltin dilaurate and stannous octoatemay be used to assist prepolymer formation and a non-reactive solventmay be added before or after prepolymer formation to control theviscosity. Suitable solvents which may be used include acetone,methylethylketone, dimethylformamide, ethylene carbonate, propylenecarbonate, diglyme, N-methylpyrrolidone, ethyl acetate, ethylene andpropylene glycol diacetates, alkyl ethers of ethylene and propyleneglycol monoacetates, toluene, xylene and sterically hindered alcoholssuch as t-butanol and diacetone alcohol. The preferred solvents arewater-miscible solvents such as N-methylpyrrolidone, dimethyl sulphoxideand dialkyl ethers of glycol acetates or mixtures of N-methylpyrrolidoneand methyl ethyl ketone.

The nonionic water-dispersible polyurethane prepolymers of the inventionmay be used in the preparation of aqueous polyurethane dispersions.

Thus, in a third aspect of the invention, there is provided an aqueousdispersion of a nonionic, water-dispersible polyurethane wherein thepolyurethane is the reaction product of:

(a) a nonionic, water-dispersible, isocyanate-terminated polyurethaneprepolymer formed by reacting:

(i) an organic polyisocyanate;

(ii) at least one organic polyol having a molecular weight in the range62 to 6000, and

(iii) a dispersing agent of Formula I; and

(b) an active hydrogen containing chain extender.

The aqueous dispersions of the invention may be prepared by dispersingthe nonionic, water dispersible, isocyanate-terminated polyurethaneprepolymer in an aqueous medium and chain extending the prepolymer witha active hydrogen containing chain extender.

The prepolymer may be dispersed in water using techniques well known inthe art. Preferably, the prepolymer is added to the water with agitationor, alternatively, water may be stirred into the prepolymer.

The active hydrogen containing chain extender which is reacted with theprepolymer is suitably a polyol, an amino alcohol, ammonia, a primary orsecondary aliphatic, alicyclic, aromatic, araliphatic or heterocyclicamine especially a diamine, hydrazine or a substituted hydrazine.Water-soluble chain extenders are preferred, and water itself may beeffective.

Examples of suitable chain extenders useful herein include ethylenediamine, diethylene triamine, triethylene tetramine, propylene diamine,butylene diamine, hexamethylene diamine, cyclohexylene diamine,piperazine, 2-methyl piperazine, phenylene diamine, tolylene diamine,xylylene diamine, tris(2-aminoethyl) amine, 3,3'-dinitrobenzidine,4,4'-methylenebis(2-chloroaniline), 3,3'-dichlorobenzidine,2,6-diaminopyridine, 4,4'-diaminodiphenylmethane, menthane diamine,m-xylene diamine and isophorone diamine. Also, materials such ashydrazine, azines such as acetone azine, substituted hydrazines such as,for example, dimethyl hydrazine, 1,6-hexamethylene-bis-hydrazine,carbodihydrazine, hydrazides of dicarboxylic acids and sulfonic acidssuch as adipic acid mono- or dihydrazide, oxalic acid dihydrazide,isophthalic acid dihydrazide, tartaric acid dihydrazide, 1,3-phenylenedisulfonic acid dihydrazide, omega-amino-caproic acid dihydrazide,hydrazides made by reacting lactones with hydrazine such asgamma-hydroxybutyric hydrazide, bis-semi-carbazide, bis-hydrazidecarbonic esters of glycols such as any of the glycols mentioned above.

Where the chain extender is other than water, for example a diamine orhydrazine, it may be added to the aqueous dispersion of prepolymer or,alternatively, it may already be present in the aqueous medium when theprepolymer is dispersed therein.

The chain extension can be conducted at elevated, reduced or ambienttemperatures. Convenient temperatures are from about 5° to 95° C. ormore, preferably from about 10° to about 45° C.

The amount of chain extender employed should be approximately equivalentto the free-NCO groups in the prepolymer, the ratio of active hydrogensin the chain extender to NCO groups in the prepolymer preferably beingin the range from 1.0 to 2.0:1. Of course when water is employed as thechain extender, these ratios will not be applicable since the water,functioning both as chain extender and dispersing medium, will bepresent in a gross excess relative to the free NCO groups.

It will be appreciated by those skilled in the art that the nonionic,water-dispersible polyurethane may be either linear, branched orcrosslinked in structure depending upon the components used in itsformation. Polyurethanes having a degree of branching of up to onecrosslink for each 3000 atomic weight units are of greatest interest.

The polyurethane may also, depending upon the components used, containfree acid or tertiary amino groups, such groups being crosslinkable inconventional manner. Particularly suitable acid groups are carboxylicacid groups. Any free acid or tertiary amino group content is suitablyin the range from 5 to 180 milliequivalents per 100 g.

In a further variant, any free acid or tertiary amine groups present inthe polyurethane may be converted to salt groups which enhance thewater-dispersibility . Thus, polyurethanes containing carboxylic acidgroups may be neutralised with, for example, tertiary amines so that thepolyurethane has not only a nonionic but also an anionic hydrophiliccentre. The production of carboxy-containing polyurethanes is well knownin the art. Such polyurethanes as adapted by the present inventiontypically being derived from prepolymers comprising reaction productsof:

(i) an organic polyisocyanate;

(ii) at least one organic polyol having a molecular weight in the range62 to 6000,

(iii) a dispersing agent of Formula I; and group containing diol ortriol .

(iv) a carboxy group containing diol or triol.

Suitable carboxy group containing diols and triol are well known andinclude dimethylolpropionic acid.

Polyurethanes containing not only a nonionic but also a cationichydrophilic centre may also be prepared in known manner.

The aqueous dispersions of the invention may be advantageously employedas coating compositions, for which purpose they may be further dilutedwith water and/or organic solvents, or they may be supplied in moreconcentrated form by evaporation of water and/or organic components ofthe liquid medium. As coating compositions, they may be applied to anysubstrate including wood, metals, glass, cloth, leather, paper,plastics, foam and the like, by any conventional method includingbrushing, dipping, flow coating, spraying and the like. The compositionsmay contain other conventional ingredients including organic solvents,pigments, dyes, emulsifiers, surfactants, thickeners, heat stabilizers,levelling agents, anti-cratering agents, fillers, sedimentationinhibitors, UV absorbers, antioxidants and the like introduced at anystage of the production process or subsequently. It is possible toinclude an amount of antimony oxide in the dispersions to enhance thefire retardant properties. The dispersions may also be used as adhesivesfor materials such as polypropylene, polyester, polyurethane, leatherand the like or as binding agents for various particulate materials.

The dispersions, which suitably have solids contents of from about 20 to60% by weight, preferably from about 25 to 50% by weight, are stableover a wide pH range (2-13) and are substantially unaffected byelectrolytes.

Those products containing free acid groups, for example --COOH groups,can be reacted with melamines, polyisocyanates, carbodiimides,polyaziridines, polyepoxides or polyvalent metal ions, for examplealuminium, magnesium, barium, beryllium, cobalt, lead, copper orantimony and especially zinc, zirconium or calcium. Similarly, productscontaining free tertiary amino groups may be reacted withpolyhalogenated hydrocarbons so as to quaternise the amino groups.Suitable polyhalogenated hydrocarbons include α,α'-dichloro-1,4-xylene,α,α'-dichloro-1,2-xylene, 1,5-dibromopentane and 1,4-dibromobutane. Thecrosslinking reactions can take place at room temperature or can beaccelerated by heat. The crosslinked polymers are thermoset in natureand have a high degree of solvent resistance.

If desired, the polyurethane dispersions of the invention may be used inadmixture with other dispersions, for example dispersions of vinylpolymers and copolymers.

Thus, in a further aspect of the invention, there is provided an aqueouspolymer dispersion containing a water dispersible polyurethane and avinyl polymer, the polyurethane being the product of reacting

(a) a water-dispersible. isocyanate-terminated polyurethane prepolymerformed by reacting:

(i) an organic polyisocyanate;

(ii) at least one organic polyol having a molecular weight in the range62 to 6000, and optionally a carboxy group containing diol or triol and

(iii) a dispersing agent of Formula I; and

(b) an active hydrogen containing chain extender.

The aqueous polymer dispersions may be prepared by simply blending anaqueous dispersion of a water-dispersible polyurethane as describedabove with an aqueous dispersion of a vinyl polymer. It is preferred,however, to polymerise one or more vinyl monomers in the presence of theaqueous polyurethane dispersion. This may be effected by adding thevinyl monomer or monomers to the polyurethane dispersion, eithergradually or all at once, and subjecting the monomer to polymerisationconditions during and/or after its addition to the dispersion.Alternatively, a solution of prepolymer in vinyl monomer may bedispersed in an aqueous medium after which the prepolymer is chainextended and the vinyl monomer polymerised.

Vinyl monomers which may be polymerised to form the vinyl polymercomponent of the aqueous dispersions of the invention include anyradically polymerisable olefinically unsaturated compounds or mixturesthereof. Thus, there may be mentioned hydrocarbon monomers, for examplebutadiene, isoprene, styrene and divinyl benzene, acrylic andsubstituted acrylic monomers, for example acrylic and methacrylic acids,acrylonitrile, methyl, ethyl, 2-hydroxyethyl, butyl and isobutylacrylates and methacrylates, acrylamide, methacrylamide,N-methylolacrylamide and other commonly used monomers such as vinylchloride, vinylidene chloride, vinyl esters, vinyl ethers, vinyl ketonesand heterocyclic vinyl compounds.

Polymerisation of the vinyl monomer or monomers may be effected usingconventional polymerisation techniques. Thus, the monomer may becontacted with free radical initiators, especially initiatorspartitioned between the aqueous and organic phases, for example acombination of t-butylhydroperoxide, isoascorbic acid and Fe.EDTA orwater-soluble initiators such as persulphates.

The weight ratio of polyurethane to vinyl polymer in the dispersions ofthe invention is suitably in the range from 9:1 to 1:9 with a solidscontent in the range from about 30% to about 45% by weight. Viscositiesare usually between 20 and 1000 cps at 25° C. and the pH is commonlyaround 7.5 to 9.0.

The aqueous polymer dispersions may be utilised for purposes similar tothose described for the nonionic polyurethane dispersions. Thus, theymay be used as coating compositions, adhesives, binding agents and thelike.

The invention is illustrated but not limited by the following Examples

Example 1

1307.6 g of a polyoxyalkyleneamine of the formula: ##STR14## availablefrom the Texaco Chemical Company as Jeffamine M-1000 was charged to areactor and heated to 130° C. Ethylene oxide (65.5 ml) was added in oneportion. The reaction was complete after 6 hours and the molten producthaving the structure: ##STR15## was then discharged from the reactor.

Example 2

100 g of Jeffamine M-1000 was reacted with ethylene oxide (40 ml) underthe conditions described in Example 1. The reaction, which was completeafter 12 hours, gave a product having the structure: ##STR16##

Example 3

A prepolymer solution was prepared for comparative purposes using aknown dispersing agent. In the preparation, 46.2 g of isophoronediisocyanate, 101.4 g of polypropylene glycol of molecular weight 1200,52.4 g of a dispersing agent (obtained by reacting 2 moles of isophoronediisocyanate with 1 mole of methoxypolyethylene glycol of molecularweight 750 and 1 mole of diethanolamine) and 85,7 g ofN-methylpyrrclidone were charged to a stirred reaction flask undernitrogen at ambient temperature. The flask was then heated to 60°-65° C.and 1.66 g of dibutyltin dilaurate were added. The temperature wasallowed to rise to 90° C. and was then maintained at 90°-95° C. for 2hours. The prepolymer solution (NCO content 1.64%) was allowed to coolto 40°-45° C. and 205 g were added over 30 minutes to 500 g of stirreddistilled water at 20-25° followed by 1.80 g hydrazine monohydrate. A10° exotherm was observed, the dispersion then being stirred for 2 hoursafter which time it had cooled to 25° C. The product was designatedDispersion A.

Dispersions B and C were prepared in the same way as Dispersion A butreplacing the dispersing agent by the dispersing agents described inExamples 1 and 2 respectively.

The three dispersions had the following properties.

    ______________________________________                                        % Agent                                                                       by weight        % Solids  Particle Size                                      in prepolymer    by weight (μm)                                            ______________________________________                                        A     26.2           19.4      0.115                                          B     24.3           19.4      0.044                                          C     25.1           18.8      0.038                                          ______________________________________                                    

The thermal stabilities of the dispersions were as follows:

    ______________________________________                                        40° C.   60° C.                                                                           80° C.                                       ______________________________________                                        A      √     X(20 min) X(20 min)                                       B      √     √  √                                        C      √     √  √                                        ______________________________________                                         √ = no coagulation after 6 hours                                       X = coagulation before 6 hours                                           

The particle size and thermal stability figures show that the dispersingagents of the invention have given finer and more stable dispersionsthan was given by the prior art agent.

Example 4

2-Hydroxyethyl acrylate (23.2 g, 0.2 mol) was added in one portion to astirred solution of a polyoxyalkyleneamine of the formula: ##STR17##available from the Texaco Chemical Company as Jeffamine M-1000 (200 g,0.2 mol) in toluene (400 ml) at 70° C. After 24 hours, the solvent wasremoved in vacuo at 50° C. to give a colourless waxy solid.Spectroscopic analysis confirmed the product to be the Michael additionadduct of the two starting materials.

Example 5

Tripropylene glycol diacrylate (10 g, 33 mmol) was added in one portionto a stirred solution of Jeffamine M-1000 (73.7 g, 74 mmol) in toluene(200 ml) at 70° C. After 24 hours, the solvent was removed in vacuo at50° C. to give a colourless waxy solid. Spectroscopic analysis confirmedthe product to be the Michael addition adduct of the two startingmaterials.

Example 6

A prepolymer solution was prepared for comparative purposes using aknown dispersing agent. In the preparation, 46.2 g of isophoronediisocyanate, 101.4 g of polypropylene glycol of molecular weight 1200,52.4 g of a dispersing agent (obtained by reacting 2 moles of isophoronediisocyanate with 1 mole of methoxypolyethylene glycol of molecularweight 750 and 1 mole of diethanolamine) and 85,7 g ofN-methylpyrrolidone were charged to a stirred reaction flask undernitrogen at ambient temperature. The flask was then heated to 60°-65° C.and 1.66 g of dibutyltin dilaurate were added. The temperature wasallowed to rise to 90° C. and was then maintained at 90°-95° C. for 2hours. The prepolymer solution (NCO content 1.64%) was allowed to coolto 40°-45° C. and 205 g were added over 30 minutes to 500 g of stirreddistilled water at 20°-25° followed by 1.80 g hydrazine monohydrate. A10° exotherm was observed, the dispersion then being stirred for 2 hoursafter which time it had cooled to 25° C. The prepolymer used in thepreparation of this dispersion contained 26.2% by weight of Agent A.Corresponding dispersions were prepared from prepolymers in which AgentA was replaced by the dispersing agents described in Examples 4 and 5respectively (Agents B and C). The three dispersions had the followingproperties.

    ______________________________________                                        % Agent                                                                       by weight        % Solids  Particle Size                                      in prepolymer    by weight (μm)                                            ______________________________________                                        A     26.2           19.4      0.115                                          B     24.3           19.4      0.044                                                25.1           18.8      0.038                                          ______________________________________                                    

The thermal stabilities of the dispersions were as follows:

    ______________________________________                                        40° C.   60° C.                                                                           80° C.                                       ______________________________________                                        A      √     X(20 min) X(20 min)                                       B      √     √  √                                        C      √     √  √                                        ______________________________________                                         √ = no coagulation after 6 hours                                       X = coagulation before 6 hours                                           

Example 7

1000 g of a polyoxyalkyleneamine of the formula

    CH.sub.3 O(C.sub.2 H.sub.4 O).sub.45.5 (CH.sub.2).sub.3 NH.sub.2

was charged to a reactor and heated to 130° C. Ethylene oxide (50 ml)was added in one portion. The reaction was complete after 6 hours andthe molten product having the structure:

    CH.sub.3 O(C.sub.2 H.sub.4 O).sub.45.5 (CH.sub.2).sub.3 N(C.sub.2 H.sub.4 OH).sub.2

was discharged from the reactor.

Example 8

1000 g of a polyoxyalkyleneamine of the formula

    CH.sub.3 O (C.sub.2 H.sub.4 O).sub.68 (CH.sub.2).sub.3 NH.sub.2

was charged to a reactor and heated to 130° C. Ethylene oxide (34 ml)was added in one portion. The reaction was complete after 6 hours andthe molten product having the structure:

    CH.sub.3 O (C.sub.2 H.sub.4 O).sub.68 (CH.sub.2).sub.3 N(C.sub.2 H.sub.4 OH).sub.2

was discharged from the reactor.

Example 9

465.7 g of a hydroxy acrylate of the formula:

    CH.sub.2 ═CHCOOC.sub.2 H.sub.4 O(CO (CH.sub.2).sub.5 O).sub.2 H

available from the Union Carbide chemical company as TONE M-100 wasadded in one portion to stirred Jeffamine M-1000 (13549) at 70° C. Themixture was stirred and heated at 70° C. for a further 18 hours. Thecooled product was a colourless waxy solid and was shown byspectroscopic analysis to be the Michael addition adduct of the twostarting materials.

Example 10

198 g of 2-hydroxypropyl acrylate was added in one portion to stirredJeffamine M-1000 (1520 g) at 80° C. After 18 hours at 80° C., themixture was cooled to give a colourless waxy solid. The structure of theproduct was shown to be the Michael adduct of the two starting materialsby spectroscopic analysis.

Example 11

1169 g of 2-hydroxyethyl acrylate was added in one portion to 2091 g ofa polyoxyalkyleneamine of the formula:

    CH.sub.3 O (C.sub.2 H.sub.4 O).sub.45.5 (CH.sub.2).sub.3 NH.sub.2

at 80° C. The mixture was stirred and heated at 80° C. for a further 18hours The cooled product was a colourless waxy solid and was shown byspectroscopic analysis to be the Michael addition product of the twostarting materials.

Example 12

A mixed non-ionically and anionically stabilised dispersion was preparedfrom a pre polymer solution using the dispersing urgent of structure:##STR18## In the preparation, 50.08 g of isophorone diisocyanate, 4.36 gof dimethylolpropionic acid, 67.59 g of polytetrahydrofuran of molecularweight 1000, 27.96 g of the above dispersing agent and 37.5 g ofN-methylpyrrolidone were charged to a stirred reaction vessel undernitrogen at ambient temperature. The flask was then heated to 60°-65° C.and 1.8 g of dibutyltin dilaurate were added. The temperature wasallowed to rise to 90° C. and was maintained at 90°-95° C. for 2 hours.The prepolymer solution was allowed to cool to 40°-45° C. and 3.29 g oftriethylamine was added. 185 g of the prepolymer were added to 450 g ofstirred water at 20°-25° C. followed by 4.41 g of hydrazine monohydrate.The dispersion had a particle size of 0.058 μm, contained 29% w/w solidsand was stable to the addition of acid.

Example 13

A prepolymer solution was prepared using the diol dispersing agent ofstructure: ##STR19## In the preparation, 38.85 g of isophoronediisocyanate, 87.38 g of polytetrahydrofuran of molecular weight 1000,23.77 g of the above mentioned dispersing diol and 64.29 gN-methylpyrrolidone were charged to a stirred reaction vessel undernitrogen at ambient temperature. The flask was then heated to 60°-15° C.and 1.4 g of dibutyltin dilaurate were added. The temperature wasallowed to rise to 90° C. and was then maintained at 90°-95° C. for 2hours. The prepolymer solution (NCO content 1.76%) was allowed to coolto 40°-45° C. and 205 g were added over 30 minutes to 500 g of stirreddistilled water at 20°-25° C. followed by 2.8 g of hydrazinemonohydrate. A 10° exotherm was observed, the dispersion then beingstirred for 2 hours after which time it had cooled to 25° C. Thedispersion had a particle size of 0.135 μ m and contained 29 w/w%solids.

Example 14

Preparation of : ##STR20## A 2 liter three-neck flask fitted with amechanical stirrer, thermometer, air ebullator, a distillation head atopa metallised vacuum jacketed column was charged with 1000 g ofpolyethylene glycol methyl ether of molecular weight 1000, 240 g ofmethyl acrylate and 1.24 g of Topanol 0. The mixture was heated toreflux to remove residual water by azeotropic distillation.Tetraisopropyltitanate (6 g) was added and the solution maintained atreflux. The head temperature, initially at 80° C., dropped to 64° C. asmethanol was generated. The distillation head was adjusted such that allthe distillate was collected below 65° C. Once the theoretical amount ofmethanol had been removed, the mixture was vacuum stripped to removeunreacted methyl acrylate.

The mixture was cooled to 60° C. and 61 g of ethanolamine were added tothe stirred mixture. The mixture was stirred and heated for a further 18hours. The product on cooling was isolated as a waxy solid and was shownby spectroscopic techniques to be the Michael addition adduct ofethanolamine and the acrylate of polyethylene glycol methyl ether 100.

Example 15

Into a dry 3 necked round bottom flask under nitrogen was charged 8.07 gdimethylol propionic acid, 20.31 g of polypropylene glycol 1200, 31.50 gof the dispersing agent described in Example 4 (eq wt =558 gmol⁻¹),40.12 g isophorone diisocyanate, 42.86 g N-methylpyrrolidone. Themixture was heated with agitation to 65°-70° C. and 1.44 g of dibutyltindilaurate in NMP (10% w/w) was added. The reaction was seen to exothermand was subsequently held at 90°-95° C. for 1 hour at which time afurther 1.44 g of dibutyltin dilaurate in NMP was added. After a further3 hours at temperature, the reaction was monitored by determination ofthe free isocyanate using the dibutyl amine method and was found to becomplete (%NCO found =3.81, % NCO theoretical=3.90%).136.9 g of theabove prepolymer was then dispersed in distilled water (212.86 g) over a30 minute period (T prepolymer=60° C.-65° C.; T water=20° C.). Upondispersion, 2.98 g of 64% hydrazine was added and a 10° C. exothermnoted. The dispersion had a solids content of 26.8%, particle size of65nm and a pH =4.9.

The urethane-acrylate was prepared using a seed-batch technique. To a500ml reactor flask under nitrogen was charged 75 g of the nonionicpolyurethane prepared as described above, 1381 g distilled water and thetemperature raised to 40° C. with agitation 1.61 g of a 1% ferroussulphate solution (0.02 wt-% on total monomer) and 0.51 g triethylenetetramine were charged to the vessel. 8.04 g of a 1% solution ofi-ascorbic acid (0.3 wt. % on monomer), 5.47 g of a 35% solution oft-butyl hydroperoxide solution (0.5 wt-% on monomer) and 18.76 g butylacrylate with 8.84 g vinylidene chloride were added rapidly over a 5minute period. An exotherm of 10.5° C. was observed. Once thetemperature had fallen to 42° C. the addition of additional i-ascorbicacid solution, t-butyl hydroperoxide solution and monomer as outlinedabove was repeated and an exotherm of 8.8° C. observed. The procedurewas repeated a third time with an exotherm of 7.2° C. being observed.The reaction was then held at 40° C. for a further 1 hour. The productwas subsequently filtered (50 μm mesh) with <1 g of coagulum recovered.The resulting dispersion had a solids content of 29.1% w/w (% monomerconversion=97), a particle size of 260mm and a pH of 6.1

We claim:
 1. A non-ionic dispersing agent having the general formula:##STR21## wherein R¹ represents a a C₁ -C₄ alkyl radical;R² representshydrogen or a mixture thereof with methyl and/or ethyl, at least 40% ofthe R² substituents in said mixture being hydrogen; R³ represents anisocyanate-reactive organic radical; R⁴ represents H or anisocyanate-reactive organic radical; Z represents 1,2-propylene; m is aninteger from 5 to 150, and n is 0 or
 1. 2. A dispersing agent accordingto claim 1 wherein R¹ is methyl.
 3. A dispersing agent according toclaim 1 wherein at least 60% of the R² substituents are hydrogen atoms.4. A dispersing agent according to claim 1 wherein R³, and R⁴ when nothydrogen, is an organic radical containing --OH, --SH, --COOH, --PO₃ H₂or --NHR in which R is hydrogen or optionally substituted alkyl.
 5. Adispersing agent according to claim 4 wherein the hydroxy-containingorganic radical is hydroxyalkyl or hydroxyalkoxycarbonylalkyl.
 6. Adispersing agent according to claim 1 having the formula: ##STR22##wherein R¹, R², Z and m are as defined in claim 1;R⁵ representshydrogen, methyl or ethyl; p is an integer from 1 to 100, and x is 1 or2.
 7. A dispersing agent according to claim 6 wherein Z is a 1,2polypropylene radical of which the secondary carbon atom is attached tothe nitrogen atom.
 8. A dispersing agent according to claim 1 having theformula: ##STR23## wherein R¹, R², Z and m are as defined in claim 1;R⁶represents hydrogen, halogen or C₁₋₄ - alkyl; Q represents a divalentelectron-withdrawing group; T represents a divalent hydrocarbon radicalwhich may carry substituents or contain hetero atoms; XH represents anisocyanate-reactive group, and x is 1 or
 2. 9. A dispersing agentaccording to claim 1 having the formula: ##STR24## wherein R¹, R², R⁶,Z, Q, T, and m are as defined in claim
 8. 10. A dispersing agentaccording to claim 8 or claim 9 wherein Z is a 1,2-propylene radical ofwhich the secondary carbon atom is attached to the nitrogen atom.
 11. Adispersing agent according to any of claims 8 to 9 wherein R⁶ ishydrogen or methyl.
 12. A dispersing agent according to claim 1 havingthe formula: ##STR25## wherein R¹, R², R³, R⁴, Z and m are as defined inclaim
 1. 13. A dispersing agent according to claim 12 wherein R³ ishydroxyethyl and R⁴ is hydrogen or hydroxyethyl.